Dental Studies Give Clues About Christopher Columbus's Crew

The first planned colonial town in the New World was founded in 1494, when about 1,200 of Christopher Columbus's crew members from the 17 ships that made up his second journey to the Americas settled on the north coast of what is now the Dominican Republic .

Beset by mutiny, mismanagement, hurricanes and disease, the settlement of La Isabela lasted only a few years. The ruins remained largely intact until the 1950s, when a local official reportedly misunderstood the order from dictator Rafael Trujillo to clean up the site in preparation for visiting dignitaries, and had them mostly bulldozed into the sea. Little remained but the skeletons below ground in the church cemetery, which lay undisturbed until excavations began in 1983.

In the past few years, sophisticated chemical studies of the skeletons, especially their teeth, have begun to yield new insights into the lives and origins of Columbus's crew. The studies hint that, among other things, crew members may have included free black Africans who arrived in the New World about a decade before the slave trade began.

La Isabela was not the first settlement established by Columbus. When the Santa Maria ran aground off Hispaniola on Christmas Eve, 1492, during his first voyage, the 39 stranded sailors built a fort they christened La Navidad. When Columbus returned the next year, the fort had been burned and the crew massacred.

The study of the La Isabela skeletons grew out of a project in Mexico's Yucatan peninsula, where in 2000 researchers were surprised to find the remains of West Africans among those buried in a mid-16th-century church cemetery in Campeche. Vera Tiesler and Andrea Cucina from the Autonomous University of Yucatan invited T. Douglas Price, director of the Laboratory for Archaeological Chemistry at the University of Wisconsin at Madison, to do isotopic analysis of those skeletons' teeth.

Isotopes are different forms of an element, atoms with different molecular weights based on their varying numbers of neutrons. Depending on their diet and water supply, humans concentrate specific isotopes in varying ratios in the enamel of their teeth while young, and those ratios remain largely unchanged throughout life.

For example, the ratio of strontium isotopes indicates whether the person grew up in a region underlain by very old bedrock, such as West Africa, or newer rock, such as Latin America. That is because older rock has a higher ratio of strontium 87 to strontium 86.

Ratios of carbon isotopes in the teeth, meanwhile, reflect what foods a person ate. A diet heavy in corn, sorghum and other tropical plants yields more carbon 13, whereas grains such as barley and wheat produce more carbon 12. Europeans of Columbus's time would have relatively little carbon 13 in their teeth; Mexicans would have much of the heavier isotope. Natives of Hispaniola and many Africans, who are believed to have eaten a mixed diet, would probably fall somewhere in between.

"Mexicans are about as heavy [on carbon 13] as you can get," said James Burton, a geochemist at the University of Wisconsin involved in the La Isabela and Campeche projects. "Africans are in between, Europeans at the other end. If people in Hispaniola had a mixed diet, manioc along with corn, that makes them hard to tell in carbon from Africans."

Scientists are also analyzing the oxygen composition of the teeth.

Oxygen isotopes in water differ according to a region's climate, with warmer climates yielding water with more "heavy oxygen" (oxygen 18) and cooler areas having "lighter oxygen" (oxygen 16). That's because it essentially takes more energy (heat) to evaporate water with heavier oxygen isotopes from the ocean into the atmosphere. At higher latitudes, higher elevations and increasing distance from the ocean, water has relatively less heavy oxygen.

Based on such analyses, scientists are certain that a number of people found in the Campeche cemetery were African. It looks highly possible they have found at least three Africans in La Isabela as well, although Burton warns against jumping to conclusions.